As Daniil Medvedev will become World's No. 1 Tennis Player on February 28, 2022, it will also be the first time that a player outside ‘Big Four’ of Roger Federer, Rafael Nadal, Novak Djokovic, and Andy Murray will be ranked as No. 1 Tennis Player in men.
source https://www.jagranjosh.com/current-affairs/russias-daniil-medvedev-replaces-novak-djokovic-as-worlds-no-1-tennis-player-1645858644-1